BPX divertor design and R&D program

The conceptual design activities for the Burning Plasma Experiment (BPX) divertor have focused on maximizing its power handling capability. As part of this design optimization process, alternative power handling approaches, plasma facing surface materials, and methods for sweeping the separatrix across the divertor surface were examined. The reference passively cooled design concept which utilizes a single-pass sweep of the separatrix across the divertor surface is shown to be the best design approach for BPX. Pyrolytic graphite annealed at 3000 degrees C for 1 h and unidirectional carbon-carbon composites are the two leading plasma facing material candidates. The design improvements considered were shown to be quite marginal and are either impractical or introduce complexities that are judged to be too costly or difficult. Initial divertor R&D program efforts are described. These initial efforts will be completed prior to the Preliminary Design Review (PDR), which is scheduled for late 1994. R&D activities following PDR are dedicated to developing remote maintenance equipment and procedures. >